The patent applications FR2 988 862 and FR2 988 874 disclose methods for locating mobile utensils that are presented before a network of magnetometers having N triaxial magnetometers mechanically connected to one another without any degree of freedom in order to preserve a known distance between each of the magnetometers, each utensil having at least one magnetic object, where N is an integer greater than or equal to five. The known methods involve iterating steps a) and b) as defined below at successive instants in time in order to obtain the estimated values of each variable at the various successive instants.
Step a) includes the measurement, by each of the magnetometers, of the amplitude of the magnetic field along each of its measurement axes,
Step b) includes the estimation, on the basis of the measurements from the magnetometers, of the values of a plurality of variables by resolving a current system of equations connecting the variables to each measurement from a triaxial magnetometer of the network, the variables corresponding to the positions, orientations and amplitudes of the magnetic moments of the magnetic objects of the utensils to be located.
These methods work particularly well. In particular, the methods are capable of locating numerous different mobile magnetic objects and therefore numerous utensils. Moreover, they are also capable of simultaneously locating a plurality of mobile utensils that are mechanically independent of one another. On account of these capabilities, the methods are referred to as “flexible”.
In order to be capable of simultaneously locating numerous mobile utensils, the system of equations has numerous variables to be estimated. Typically, for each magnetic object of the utensil to be located, the system of equations has six variables to be estimated.
The estimation of the values of the numerous variables of the system requires the execution of a large number of operations by the computer because the system of equations is nonlinear. In point of fact, the greater the number of operations to be executed by the computer, the more the power consumption of the computer increases.